Fifteen members of the radical Jewish group Lehava suspected of attacking and threatening Arab men dating Jewish women have been arrested in Israel, including the group’s controversial leader, Ben-Tzion Gopstein.

The raids and arrests were carried out simultaneously in Jerusalem, northern and southern Israel and in Jewish settlements in the occupied West Bank.

“Fifteen suspects known to the police as active in the Lehava organization were arrested or detained for questioning during the night as part of a police investigation on suspicion that they acted to locate and threaten [Arab] minority members with connections to Jewish young women or girls,” read a police statement, as quoted by AFP.

The raids, the police said, were the result of an undercover operation that uncovered evidence of “organized and pre-meditated activity believed to have been carried out by the suspects, known members of Lehava.”

Ben-Tzion Gopstein, Lehava’s leader, insists that he has done nothing wrong and claimed the police had “succumbed to pressure from the extreme left,” according to Haaretz.

Gopstein has previously gotten into trouble with the law on multiple occasions. In 2014, he was arrested for racist incitement and later charged with trying to stop a police officer from carrying out their duty, while in 2015 he was investigated for condoning burning churches to the ground in accordance with ancient Jewish commandment against “idol worship.” Last year, he was also acquitted of an assault on two left-wing activists.

In addition to his run-ins with the law, Gopstein has also led protest marches against gay pride events and the LGBT community.

Founded in 2009, Lehava, a Hebrew acronym for “To Prevent Assimilation in the Holy Land,” is opposed to interracial and inter-religious marriage. At a wedding between a Muslim man and Jewish woman in Tel Aviv in 2014, its members staged a protest rally yelling “Death to Arabs!” In addition to harassing minorities, the group also provides “safe houses” for Jewish women getting out of relationships with Arabs, and has attempted to portray this as a national scourge, Haaretz reports.

Lehava has also been accused of spreading anti-Arab and anti-Christian propaganda. In April, some Israelis were arrested for allegedly attacking Arabs with knives and other weapons after watching one of their videos.

In July, the Israel Religious Action Center filed a petition to the High Court of Justice for Gopstein to be charged with incitement to racism and violence and for Lehava to be declared a criminal organization.